Fabrics and textiles become soiled over time and need to be cleaned. The cleaning operation removes dirt from the fibers, but in the process, fibers are dislodged from the woven and knit fabrics or textiles, resulting in lint, fuzz, or pills which remain on the surface of the material. In addition to the loss of fibers, the cleaning process can also remove some of the dyes, resulting in a fading of the fabric. Both mechanisms are detrimental to the fabric and result in an undesirable appearance.
Detergents are formulated with additives designed to associate with the fibers, and diminish the effect of wear, fiber loss, pilling and color-loss. An effective protective additive must a) have the ability to associate with the surface of the fibers, and not be easily removed, and b) must not adversely effect detergency or cleaning properties of the detergent, in other words must not attract dirt and other soils back onto the fibers.
One means of associating the protective additive to the fiber is to take advantage of the anionic nature of the fiber. Additives containing cationic moieties will be attracted to, and associate with, the anionic fibers, thus providing some protection to the fibers. Detergents containing linear polyamines are used in laundry detergent applications using this principal. The use of polyamines for this application is described in WO 99/14297, WO 00/49124, and U.S. Pat. No. 6,140,292.
WO 00/56849 discloses laundry detergent compositions having cationically charged polymers. The polymers are amine-containing homopolymers, copolymers, or the quaternized derivatives thereof. The objective of this application is to maximize the cationic component of the polymer, to increase the association between the polymer and the fibers. Anions are only disclosed in association with quaternized polymers.
Unfortunately, the cationic polymer additives also attract dirt; thus dirt which has been removed from the laundry is attracted back to the cationic polymer, and thus back to the clothes.
Another approach for associating a polymeric protective additive with fibers is to take advantage of the relative hydrophobic nature of the fibers compared to the aqueous environment of the wash liquor. A hydrophobic polymer will associate with fibers and will minimize exposure to the aqueous environment. On the other hand, a polymer having a high hydrophilic character, such as many of the polyamines and poly amino acids described in the art, will associate with the aqueous wash liquor, and will not deposit well onto the surface of the fibers. One way to overcome this disadvantage is to form a polymer having quaternized amines, as disclosed on WO 00/22075. Such a polymer has a high hydrophilic character, but is attracted to the fibers due to a strong cationic character. The negative side of the high cationic character is the attraction for dirt, and thus poor redeposition properties.
Polymers having a high degree of hydrophobicity are difficult to synthesize, since they tend to be water insoluble, and come out of solution when placed into an aqueous solution. The solubility of the polymer can be improved by reducing the level of hydrophobe, but this also reduces the positive fiber deposition properties associated with the hydrophobe.
Polymers having a high degree of hydrophobicity are described in U.S. patent application Ser. No. 09/920,498. The hydrophobically modified solution polymers may be used to provide color protection and anti-pilling properties to fabrics and textiles. The polymers contain at least 75 mole percent of the hydrophobic monomer, and the hydrophobic amine monomer was neutralized to improve solubility.
There is a need for a polymeric additive for protecting fibers during the cleaning process, having the proper balance between hydrophilic, hydrophobic, and cationic components to provide excellent protective properties to fibers while minimizing the negative effect on redeposition properties associated with cationic character. While not being bound to any theory, it is believed that the hydrophobe serves to minimize the interaction of the amine functionality with surfactants typically found in a detergent. The copolymer must balance the water solubility (amine groups) and the water insolubility (hydrophobic groups) on the polymer molecule, to optimize desired properties.
It has been found that an amine functional copolymer, that is at least partially neutralized, and that has greater than 20 mole percent of the amine moiety, which is balanced with a suitable level of nonionic and/or hydrophobic moieties, provides the advantage of color and wear protection to fibers, with a minimum of negative effects on redeposition properties.